Buying a Commodore 64 help!

ASM development for the Commodore 64/128
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RetrogamerRhys
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Joined: Mon Oct 07, 2019 3:35 pm

Buying a Commodore 64 help!

Post by RetrogamerRhys » Thu Oct 31, 2019 9:21 am

I'm buying a commodore 64 and I want to know how to use assembley language on it. I know it starts in Basic which is built in but I want to be able to program assembley do I need to load it off a tape or disk? Thanks.

EvilSandwich
Posts: 9
Joined: Wed Nov 13, 2019 7:36 am

Re: Buying a Commodore 64 help!

Post by EvilSandwich » Sat Nov 23, 2019 10:02 am

It depends on what your doing. Thankfully the C64 has a monitor and assembler built right into it.

On the command prompt, type without quotes "MON" to tell the machine that you want to start making an Assembly program.

The format is a tiny bit different than anything you would type in say Notepad++, but the basic format should look familiar.

Try a simple program.

.A2000 INC $D020
.A2003 JMP $2000

After every line, you'll see your code line's HEX equivalent pop up next to it after you press enter and move to the next line. That means, you did it right.

Press Return on a blank line to exit assembly mode.

Then too tell the C64 to run the program you just built, type G2000, which means "Go to memory address $2000 and execute".

Voila! $D020 is where the screen border display memory is kept! You should have flickering colors. To stop the program press Run/Stop+Restore or reset the computer!

This is important. Stay within memory address $1000-$9fff. Anything beyond that is for the C64 system and should be left alone for beginners.

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